Electrochemical Impedance Spectroscopy of Core‐Shell Nanofiber Cathodes, with Ce0.9Gd0.1O1.95 (Core) and Cu‐Doped La0.6Sr0.4MnO3 (Shell), for Application in Solid Oxide Fuel Cells

Several core-shell nanofiber electrodes are prepared through electrospinning and tested for application as intermediate-temperature solid oxide fuel cell (IT-SOFC) cathodes. The materials investigated are La0.6Sr0.4MnO3 (LSM), La0.6Sr0.4Cu0.1Mn0.9O3-delta (LSCuM_1), and La0.6Sr0.4Cu0.2Mn0.8O3-delta (LSCuM_2) perovskites, used at the shell side of the nanofibers. Ce0.9Gd0.1O1.95 (GDC10) fluorite is used as the core material. The electrochemical characterization of the core-shell nanofiber electrodes is performed through electrochemical impedance spectroscopy (EIS). The EIS results are reported and discussed based on equivalent circuit modeling. The polarization resistance of the GDC10/LSM core-shell nanofibers electrodes is R-P similar to 4.5 omega cm(2) at 650 degrees C. Improvement is accomplished with GDC10/LSCuM_1 and GDC10/LSCuM_2 core-shell nanofibers, with R-P similar to 1.8 omega cm(2) and 1.7 omega cm(2) respectively at 650 degrees C. Post-test SEM characterization is carried out, to ascertain possible degradation and identify the most promising shell perovskite.